Generally, a solar cell is used as a power source for an artificial satellite, a space station, and the like. The solar cell used for this purpose is desired to be lightweight, and a single crystal silicon solar cell with a thickness of, for example, about 0.1 mm is used. Further, in recent years, using a compound solar cell with a thickness of less than or equal to 0.05 mm has been under consideration. A plurality of such solar cells connected in series or in parallel constitute a solar cell module.
For example, when a solar cell module including a plurality of solar cells connected in series partially goes into a shadow, not only power is not generated but also a voltage is applied in an opposite direction in solar cells at the shadowed part, reducing an overall output of the solar cell module.
Further, in a solar cell module formed by connecting compound solar cells, a withstand voltage in the opposite direction is low, and the solar cells may be damaged when a voltage is applied in the opposite direction. In order to prevent such a situation, it is necessary to connect a bypass diode in parallel with each solar cell. A compound solar cell having a structure in which positive and negative electrodes of the solar cell are arranged on a light receiving surface side has been developed to facilitate connection between cells. In order to facilitate connection with such a solar cell, a bypass diode having positive and negative electrodes arranged on one surface has also been developed. For example, in a bypass diode 101 shown in FIGS. 10(a) and 10(b), a p electrode 4 and an n electrode 5 are provided on one surface of a semiconductor substrate 1.
FIG. 11 shows one example of a method for connecting solar cells and the bypass diodes. A plurality of solar cells 24 are connected by interconnectors 16, thereby constituting a solar cell module 151. To connect solar cells 24, two interconnectors 16 are interposed in parallel. One bypass diode 101 is connected to each solar cell 24. To connect one solar cell 24 and one bypass diode 101, two interconnectors 17 are interposed in parallel. Connection by interconnectors 16, 17 are performed on one surface only.
Further, as described above, a very thin compound solar cell has been developed, and a very thin bypass diode has also been developed to be suitable for the solar cell.